38 THE TONER LECTURES. 



obstructed, moist gangrene rarely follows. The foot especially 

 generally mummifies. But this is not always the case. Occa- 

 sionally the gangrene is moist from the beginning, from early 

 obliteration of the vein, or having begun as dry gangrene, e. g. 

 of the foot from a popliteal clot, suddenly both the femoral 

 artery and vein may be obstructed, and a moist gangrene of 

 the leg or thigh be added. Gangrene from venous obstruction 

 alone is very rare. It is more apt to follow in the arm than 

 the leg.^ 



Coagulation of the blood may also be caused occasionally 

 by direct mechanical causes in fevers, as in a case given by 

 Jaesche, in which a swollen gland surrounded the common 

 iliac artery at its bifurcation and caused a clot, probably by 

 direct pressure or by induced arteritis. 



2. The second varietj' of spontaneous gangrene is that in 

 which no clot apparently exists — certainly no such clot as is 

 commonly designated either an embolus or a thrombus, that is, 

 a locnl clot in an arterial trunk of some size which cuts off the 

 circulation in the tissues supplied by its branches. But oxen 

 in these cases I believe that the conditions affecting the circu- 

 lation already so fully considered, will more readil}^ and 

 rationally explain the causation of the gangrene than any 

 specific action of the indefinite though undoubted poison of 

 the fever. Coagulation I believe still to be the cause, but not 

 in the larger trunks. It begins rather as a blood stasis in the 

 capillary circulation. The parts in which the often extensive 

 coagulation takes place are at once struck with gangrene, and, 

 as the blockaded vessels themselves are all involved in the 

 general destruction of the gangrenous tissues, all evidence of 

 the nature of the lesion is thus destroyed. This form of gan- 

 grene occurs generally in the nose, ears, penis, i^erineum, 



' Hueter (Virchow's Archiv, xvii, 48) records, however, a very inte- 

 resting case of gangrene of the right log following a spontaneous clot 

 without assignable cause, the vein wall being healthy. 



